Regular concrete is a mixture of cement (binder), water and sand or gravel (filler). It is the chemical reaction between cement and water that makes concrete set and that gives it it’s strength.
Though concrete’s base ingredients are inexpensive, concrete has some properties that makes it undesirable for numerous applications. These properties are high weight (density), high thermal conductivity (poor thermal insulator) and it becomes very hard, thus it is difficult to shape or remove once it has cured.
But to counteract these sometimes undesirable properties, the filler can be replaced by something other than sand or gravel.
Cellular Lightweight Concrete
In CLC, all or part of the sand is replaced by tiny air bubbles. The more sand that is removed and the more air that is mixed in with the concrete, the lower the density. With lower density follows lower thermal conductivity and less mechanical strength.
CLC is typically produced at densities from 400 – 1800 kg/m3(25-110 pcf) as compared to regular concrete which is 2200 kg/m3
It flows easily and fills voids without need for compaction or vibration.
It must be manufactured from dry ingredients on site for predictable density and for it to attain maximum strength.
- Wide range of densities from one single foaming agent – Aercell A-7
- Compressive strengths from 2 (200) N/mm2 (psi) and up
- Flowable and self leveling
- No packing or vibrating required
- Good sound absorbation
- Easy to escavate and shape with handtools
- Freeze / thaw resistant
- Non water absorbing
- Good thermal insulation
- Unaffected by fire and high temperatures
- Monolithic, does not erode, settle or compact
Aercrete 625 CLC Machine
- Easy-to-haul trailer for on-site production
- Variable density from 400 (25) to 1800 (120) kg/m3 (pcf)
- Output capacity of up to 25 (30 ) m3/hr (yd3/hr)
- Numerically controlled, continuous volumetric mixing
- Complete system – just add water!
- Consistent results with minimal variations
- Finished end result straight from inexpensive dry materials
- Eliminates unnecessary material transport costs
- Built-in concrete pump with long reach
- User friendly computer control
- No costly set-up or tuning before each job
- No short deliveries or over runs
- No "profit sharing" with batch plants
There are two different types of foaming agents that can be used when making CLC; Organic, based on protein, or synthetic, based on surfactants.
From the outset, only protein based foaming agents were available. The proteins in this type of chemistry are animal proteins extracted as a bi-product in the meat processing industry.
Protein foam is characterized by an off-white color, a somewhat unpleasant smell and in concentrated form, a limited shelf-life after which it turns rancid. CLC made with organic foam has a greater tendency to have build-up of molds and is therefore in markets with high humidity not suitable for residential construction or in public buildings. Other markets have issues with the thought of remains from pigs or cows in walls, floors and ceilings.
Aercrete Aercell A-7
Aercrete has developed a synthetic foaming agent, Aercell A-7 that eliminates the downsides with protein foam.
Aercell is a surfactant based, stable foam with air cells in the magnitude of 60-90 microns. It is unique in that it can be used for all CLC densities from 400 (25) to 1800 (120) kg/m3 (pcf).
Aercell’s properties can be compared with dishwashing liquid. A pleasant smell, a white fresh looking foam and for this purpose an unlimited shelf life. It is completely safe to handle and also environmentally safe.
Aercete’s machines are designed to be used with Aercell A-7 and combined, they become a tried and tested solution for making CLC.